1. Field of the Invention
The present invention generally relates to an adhesive compound used to form a photoresist film on a substrate, and a method for forming a photoresist pattern using the same. More particularly, the present invention generally relates to an adhesive compound that reduces residual photoresist film on a substrate after a cleaning process, and a method for forming a photoresist pattern using the same.
A claim of priority is made to Korean Patent Application No. 2004-3012 filed on Jan. 15, 2004, the content of which is incorporated by reference.
2. Description of the Related Arts
As information processing devices have developed, semiconductor devices have also developed with higher degree of integration with rapid response speed. Hence, the technology for manufacturing the semiconductor devices has developed to improve integration, reliability, and response speed of the semiconductor devices. Accordingly, precision processing techniques, for example, a photolithography process, have become stricter.
In a conventional photolithography process, a photoresist film is formed on a substrate. Subsequently, predetermined portions of the photoresist film are removed by an exposing process and a developing process to form photoresist patterns, and then residual photoresist (developed photoresist) is then removed.
However, if properties of the substrate and the photoresist film are different, coating defects and pattern lifting may occur during a coating process and a pattern forming process, respectively. Conventionally, to improve the adhesive strength between the substrate and the photoresist film, hexamethyldisilazane (HMDS) represented by the following chemical formula (A), is coated on the substrate before the formation of the photoresist film.

The HMDS turns the surface property of the silicon substrate from hydrophilic to hydrophobic, as illustrated in the following reaction equation (1). In particular, at a high temperature, silanol (Si—OH) reacts with the surface of the substrate to transform OH functional groups into OSiMe3 functional groups. Therefore, the surface of the substrate loses its hydrogen bonding capabilities while gaining an affinity for organic materials; the photoresist adheres better to the substrate, and the adhesive strength between the substrate and the photoresist is enhanced. Also, a contact angle on the substrate increases.

Thus, through the use of HMDS, coating defects and pattern shifts are prevented by increasing the adhesive properties of the photoresist compound.
However, when the adhesive strength between the substrate and the photoresist film on a positive photoresist is increased, exposed residual photoresist may remain on the substrate even after a cleaning process. The residual photoresist causes inaccurate patterns.
Korean Laid-open Patent Publication No. 2001-7330, published on Jan. 26, 2001, discloses for example, a method of using an adhesive layer with reduced pressure adhesive polymer. The adhesive layer does not include a low molecular weight oligomeric material. According to this method, the resist material is removed without leaving any organic contaminants on the surface of the substrate. However, the employment of the above-mentioned adhesive layer is not economical, and also requires an additional process step.
Thus, an adhesive compound with good adhesive strength and efficient photoresist film removability, and an adhesive compound that does not require an additional process or treatment step are required.